The invention relates in general to an elevator control system and, in particular, to a control system which restricts floor calls at a main floor to certain destination floors.
The single car elevator system typically has a pair of up and down hall call buttons at each floor between the top floor and the bottom floor. These hall call buttons are utilized by prospective passengers to summon the elevator car. Inside the car is an array of car call buttons, one button for each floor served by the car. When two or more elevators operate in an elevator system, it is desirable to coordinate the movements of the elevators to carry out various strategies.
One type of known elevator installation has at least one elevator which services at least one main floor and a number of adjacent floors in response to command input signals for the calling of cars to the floors and for the input of travel destination wishes but is restricted to only travel to one certain group of destination floors. Such systems make it possible to realize and to operate efficient elevator installations of favorable costs, wherein the elevator users benefit from rapid service.
A control system for elevators with double cars is shown in U.S. Pat. No. 3,625,311 in which double cars can serve two adjacent floors at the same time. In this case, the filling of a building can be attained in the shortest possible time with almost uniform occupation of the double cars. At the main stopping floor, the passengers for even-numbered destination floors board the upper car and for the odd-numbered floors board the lower car, wherein the respective car call transmitters for the destination floors not associated with each car are blocked. As soon as the car stops at an upper floor, the block is cancelled so that a passenger boarding can travel to any desired destination floors in an upward direction. The cancellation, initiated by a stop at a floor, of the destination floor block has the disadvantage that the passengers which have boarded the wrong car at the main floor, can now through subsequent actuation of the car call transmitter yet get to the desired destination floors, whereby the efficiency of the elevator installation is greatly reduced.
According to U.S. Pat. No. 3,080,944, a control system for elevators with single cars switches over to zonal operation at high traffic volumes. A first zone comprises the lower floors and a second zone comprises the upper floors. A first group of elevators serves the floors allocated to the first zone and a second group of elevators serves the floors allocated to the second zone. The car call keys of the floors lying outside the respective zone are blocked electrically, whereby only travels to the floors lying within the respective zone can be carried out. During zonal operation, the first group of elevators answers no floor calls during the ascending travel and only "down" floor calls lying within the first zone during the descending travel. The second group of lifts answers all floor calls during the ascending travel and only "down" floor calls lying within the second zone during the descending travel.
The disadvantage of this system lies is that elevators of the second group, by reason of floor calls of the first zone, also stop during the ascending travel when destination requests are present which can not be carried out. The unnecessary stops arising thereby reduce the efficiency of the elevator installation.